This invention relates to a gas treatment process, and more particularly to a process for the removal of hydrogen sulphide (H.sub.2 S) from contaminated gas.
Natural gas is frequently contaminated with H.sub.2 S, particularly where the gas-bearing rock formation contains sulphates and where sulphate-reducing bacteria have entered the formation in water which is used as displacement fluid. H.sub.2 S has an objectionable smell, is toxic and produces oxides of sulphur on combustion. These factors lead purchasers not infrequently to refuse to accept gas supplies where H.sub.2 S is present at more than 5 ppm (parts per million).
In traditional gas-sweetening processes, H.sub.2 S is removed for example by use of solid zinc oxide. Although zinc oxide can be regenerated, such regeneration typically involves heating at temperatures of the order of 500.degree. C., with formation of sulphur dioxide.
Gaseous products of industrial processes may also be contaminated with H.sub.2 S.